Injector construction



March 19, 1946.-

F. A. FUDGE INJECTOR CONSTRUCTION Filed Jan. 21, 1944 EW 1 k\\\\\ w P /U m 0 J w m w w m/ w m; a g m Q w 4 g m w 01%,. 0 W rm 1 9 Patented Mar. 19, 1946 UNITED STATES PATENT OFFICE INJECTOR CONSTRUCTION Frederick A. Pudge, Boise, Idaho Application January 21, 1944, Serial No. 519,242

- combination of parts to be described hereinafter,

Claims.

This invention relates to an injector construction for injecting liquid fuel through an admission port into an internal combustion motor. While features of the invention are useful in the construction of motors of this general type for use in commercial purposes, certain features of the invention give it advantages in use on Diesel or semi-Diesel motors employed on aeroplanes used in combat.

In practice, motors of this general type provide means for atomizing the liquid fuel under high pressure into the combustion chamber, and in some systems at least, this necessitates the use of a system of piping in which the liquid fuel is under high pressure. Of course, if such a piping system is damaged by enemy fire or from any other reason causing a leakage, a considerable amount of the fuel could be sprayed over parts of the aeroplane which is of course, extremely dangerous as a fire hazard.

One of the objects of the present invention is to provide an injector construction and arrangement of parts cooperating therewith, which will avoid the necessity for the use of exposed pipe carrying the fuel under high pressure; and providing a construction in which the fuel may be carried to the injectors at a relativelylow pressure, the development of the high pressure being confined to the immediate vicinit of the injector, at which point the ducts and chambers'contaim ing the fuel are encased behind relatively heavy walls more Or less invulnerable to the fire of small firearms.

Another object of the invention is to provide in a construction such as referred to above, simple means for enabling the motor to be driven at different speeds by controlling the quantity of fuel delivered to the admission port into the combustion chamber.

Another object of the invention is to provide simple means associated with mechanism such as described above, for maintaining an eflicient circulation of the fuel oil around the parts of the injector so as to maintain the same in a relatively all of which contribute to produce an efficient injector construction.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawing:

Fig. 1 is a longitudinal section through an injcction mechanism embodying my invention, showing a portion of the wall of the motor cylinder broken away, and also showing portions of two opposed pistons located on opposite sides of the combustion chamber. pressure developing apparatus in a position of rest, that is to say, in a position corresponding to the minimum pressure in the compression chamber or pressure chamber in which the high pressure is developed immediately before, and during, the moment of injecting the charge into the combustion chamber.

Fig. 2 is a fragmentary view showing a part of the mechanism illustrated in Fig, l, and illustrating the pressure developing mechanism at the moment when the high pressure is developed in the pressure chamber, and injection is taking place into th combustion chamber.

Fig. 3 is a vertical section taken about on the line 3-3 of Fig. 2, and further illustrating details of the injector construction, and particularly those relating to the means for effecting movements of the control part or valve, the position of which controls the amount of fuel injected into the combustion chamber.

Fig. 4 is a perspective of the driving head of a plunger which I prefer to employ for developing a high injection pressure in the pressure chamher, and for effecting the circulation of the fuel through the chambers and ducts of the injection apparatus. In this view the shank of this plunger is broken away. y

In practicing the invention I provide a casing with a member mounted therein that is formed with a pressure chamber for the fuel. Associated with the pressure chamber, movable means is provided for developing the injection pressure in the pressure chamber; and mean is provided for controlling the quantity of fuel delivered from the pressure chamber to the admission chamber.

In the invention as illustrated in the drawing, I indicates the wall of a motor of any type, for example, a multi-cylinder motor in which case the number I would indicate the wall of one of the cylinders. In the present instance, two pistons 2 and 3 are mounted for reciprocation in This view shows the v the cylinder. and at the limit of their in-stroke their adjacent faces-4 are only a short distance apart so as to form'a combustion chamber 5 between the same intowhich the liquid fuelis admitted through an admission port i.

This admission port 6 is formed within a casing 1 that may be mounted rigidly on the outer side of the wall I. Within the casing I an arbor 8 on short shaft is mounted for rotation circuitable bearings such as the ball bearings I and i2, and this arbor is rotated continuously when the motor is running. through any suitable means such as spiral gears I I and I2, the former of which is mounted on a drive shaft I! that is driven continuously from a movingpart oi the engine.

n the central axis of .the arbor a bore is formed, the inner end of which constitutes a pressure chamber M, and at this chamber I provide means for developing the injection pressure.

In the present instance, the means for developing the inlection'f pressure consists of a plunger is. A portion of the body of this plunger is provided with a splined connection it to a counterbore l1 formed in the adjacent end oi the arbor 8 which, of course, causes the plunger I! to rotate with the arbor. The middle portion of the plunger I is guided in a counterbore l8 which, in the present instance. is of slightly smaller diameter than the splined oounterbore l1. Any suitable means may be provided for reciprocating this plunger. In the present instance, it is provided at its outer end with an enlarged head IS with a slip collar l9a against which a coil spring 20 thrusts. and this spring holds the head I! up against a-fixed cam 2i formed as a plug in a bonnet 22 that is bolted up to close this end of the casing. On its outer face the head l8 has a cam 23 which may be similar to the cam 2|. In the position of the parts shown in Fig. 1, these cams are not in action, but in Fig. 2 the cam 23 is illustrated riding on the cam 2! so as to compress the spring 20 and advance the stem 24 of the plunger up into the compression chamber M to compress the fuel therein. when the plunger or piston I5 i in its retracted position shown in Fig. 1, fuel is supplied to the pressure chamber l4 through a plurality of inclined ducts 25, the inner ends of which emerge into the chamber l4 through its wall, and the outer ends of which communicate with a fuel groove or ring 28 formed in a bore 21 in the casing, fitting the outer diameter of the arbor at this point.

This fuel ring 26 is supplied with fuel at low pressure through an inlet duct 28 to which a pipe connection 29 is connected.

The inner end of the pressure chamber I4 is provided with a delivery passage or port 30 which is in axial alignment with the admission port 6. so that at each forward stroke of the plunger l5, fuel will be discharged through the delivery passage 30 into the admission port 8 and thence into the combustion chamber. If desired, this passage 30 may communicate directly with the admission passage 6, but I prefer to provide means whereby the quantity of fuel delivered through the passage 30 may be regulated as desired, thereby enabling the motor to be readily set to run at idling speed, and an intermediate speed, or speeds, and full speed In order to accomplish this, I prefer to provide a sleeve 2| surrounding the arbor, and having a non-rotative connection to the game such as a splined connection 32. This sleeve has a plurality of ports 32 in it, any one of which can align with the delivery passage 20 so as to restrict the amount of fuel that can be delivered through it to the admission passage;

In other words, these ports 22 may include an idling port 32a, an intermediate port 22b, and a full speed port 22c. These ports are of graduated cross-section, the port 22a of course having the smallest area. In a Diesel engine oi usual design,

these ports would be very small in diameter, probably of the order of seven-thousandths of an inch in diameter or thereabouts.

In the drawing, of course these ports are illustrated greatly magnifled in size so as to indicatehow they are graduatedinsize.

Any suitable means may be employed for shifting the sleeve 2| so asto bring any one of the ports 33 into alignment with the admission passage 8. In the present instance, I have illustrated the sleeve as provided with the circumferential groove 24, and this groove carries three or more cams 35 which are carried respectively, on the inner ends of three radial shafts 36, the outer ends of which extend out through the outer wall of the casing, at which point means is provided for rotating them inunison. These cams 35 are of circular form, but are attached eccentrically to their shafts 36. With this arrangement it will be evident that if the shafts 28 are rotated in unison, they will all cooperate to shift the sleeve on its splined connection 32. In order to rotate the cam shafts 36 in unison, each shaft may be provided with a small pinion 21, and these pinions all mesh with the teeth of a segment .38 that is guided for rotation in a rabbet groove 39 formed on the outer side of the easing. This segment of course is not a complete circle, as it must have a gap in its circumference to allow clearance for the neck 40 of the casing I that extends toward the wall I of the motor, and which is of much smaller dimension than the cylindrical outer portion 4! of this casing.

40 In practice, this segment would be provided with be connected up to operate in unison. In Fig.

3 the handle 42 is shown in one of its extreme positions, which would correspond to delivering fuel through either the port 330. or the port 330.

When this handle or lever 42 is in its neutral position where it is indicated in dotted lines in Fig. 3, the intermediate port 33b would be lined up with the admission port 6.

Of course, only a drop or so of fuel would ordinarily be fed from the chamber M on the forward stroke of the stem 24. and the full stroke of the stem 24 forces back the relief plunger l3 so that its inner end uncovers a by-pass port 44. This plunger 43 is pressed forwardly by a spring 45 back of it, which can be adjusted by means of an adjusting screw 46 to develop any desired pressure in the chamber It when the plunger l5 moves forward. Of course. this pressure should be high enough to insure sulficient pressure for eiiicient injection of the fuel. The port 44 leads out into a cooling chamber 41 that substantially surrounds the sleeve and to keep the same relatively cool, and from which excess fuel passes back through a pipe connection 48 to a reservoir from-which the pipe connection 38 leads off. This reservoir is not illustrated. The side of the sleeve 3| that is disposed toward the wall I of the motor, rotates against an arcuate seat 49 (see Fig. 3) If it is considered necessary in practice to press the sleeve firmly onto this seat, this can be accomplished by providing a relief valve within the fitting 50 through sure for emcient operation.

which outlet is had to the return pipe connection it. Of course. this pressure against the seat, should not be very great, but by providing a spring-loaded relief valve in this connection 0, a slight unbalance of pressure on the superfiicial area of the sleeve 8i would insure suillcient pres- However, as there is plenty of fuel being supplied to the delivery port 38 on each forward stroke of the plunger it, it is really immaterial whether any leakage of fuel occurs between the meeting faces of the arbor and the sleeve, and the face of the sleeve in contact with the seat 4s.

Of course, in the withdrawn position of the plunger it illustrated in Fig. l, a small chamber its is formed in front of the plunger it.

Of course, the liquid fuel might accumulate in this chamber and interfere with the easy operation of the plunger in its forward movement, and in order to prevent any such dimculty arising, I prefer to provide a good vent 5i indicated in dotted lines in Fig. 1, that leads from this chamber 15a out to the fuel chamber 41.

The type of engine illustrated, usually provides two shafts corresponding respectively, to each of the pistons 2 and t, and the pistons are connected by connecting rods at their. outer ends to these shafts to rotate them. When the pistons 2 and 8 move outwardly in their stroke, they uncover exhaust ports 62 indicated in dotted lines, which lead the gases of combustion out to an exhaust manifold. After the scavenging of the cylinder and the completion of the exhaust, sumcient air remains in the space between the pistons for supporting combustion when the fuel is injected through the admission passage 6.

What I claim is:

l. A liquid fuel injector construction comprising a casing, an arbor therein having a pressure chamber to which the fuel is admitted, means movably mounted at said chamber for developing injection pressure in the fuel, said arbor having a delivery passage leading from the chamber, and a sleeve mounted on the arbor having a. plurality of ducts therein of different crosssectional area, said sleeve mounted for relative movement on the arbor, with means for control ling the same to align my one of the said ducts with the said delivery passage in the arbor.

2. A liquid fuel injector construction comprising an arbor having a pressure chamber therein to which the fuel is admitted, a plunger reciprocating in said chamber for developing pressure in the fuel, with means for reciprocating the plunger; said arbor having a delivery passage leading from said chamber, and a sleeve nonrotatably mounted on the arbor and capable of shifting longitudinally on the arbor, said sleeve having a plurality of ducts therein of different cross-sectional area with means for shifting the same to align any one of the said duets with the said delivery passage in th arbor.

3. An injector construction constructed as defined inclaim 2, in which the plunger is reciprocated through the agency of a cam.

4. A liquid fuel injector construction, comprising: an arbor, saidu arbor defining apressure chamber, an intake and discharge ports there for; a piston for said pressure chamber; a sleeve carried by said arbor and covering said discharge port; a casing having and walls journalling said arbor and defining a compartment enveloping said sleeve, said casing having an arcuate wall conforming to and engaged by said sleeve, said casing having a delivery port in registry with the discharge port of said arbor; and said sleeve having a plurality of metering ports adapted to be selectively interposed between said delivery port and said discharge port. 5 5. A liquid fuel injector construction, comprising: a casing defining a chamber, a raised arcuate wall in said chamber having a delivery port: an arbor joumalled in said chamber about an axis coinciding with the center of curvature of said arcuate wall, said arbor defining, a pressure chamber, an intake and discharg ports therefor, the discharge ports positioned for periodic communication with the said delivery port as said arbor is rotated; and means defining a plurality of metering ports interposed between said arbor and said arcuate wall and axially movable to bring a selected metering port in registry with said discharge and delivery ports to form a com.- municating passage therebetween.

6. A liquid fuel injector construction for internal combustion engines, comprising: a casing defining a chamber having a fixed discharge duct in a side wall thereof; a rotary arbor journalled within said casing and having a pump chamber and outlet port therefrom adapted as said arbor is rotated to register periodically with said fixed duct; an injection pump incorporating said chamber; a sleeve rotatable with said arbor and slidable thereon, said sleeve having a plurality of ducts of difierent cross-sectional area each adapted to be moved into registr with said outlet port thereby to periodically connect said outlet port with said fixed discharge duct as said arbor and sleeve are rotated. I

7. A liquid fuel injector construction for internal combustion engines, comprising: a. casing defining a chamber having a fixed discharge duct in a side wall thereof; a rotar arbor journalled within said casing and having a pump chamber and outlet port therefrom adapted as said arbor is rotated to register periodically with said fixed duct; an injection pump incorporating said chamber; a sleeve rotatable with said arbor and slidable thereon, said sleeve having a plurality of 45 ducts of diflerent cross-sectional area each adapted to be moved into registry with said outlet port thereby to periodicall connect said outlet port with said fixed discharge duct as said arbor and sleeve are rotated, said sleeve provided with an external circumferential groove; a cam shaft journalled in said casing; and a cam thereon engageable' with said groove to efiect sliding movement of said sleeve on said arbor.

w 8. A liquid fuel injector construction for internal combustion engines, comprising: a casing structure defining a cooling chamber; an arcuate boss projecting into said cooling chamber and a fixed discharge duct in said boss; a rotary arbor w journalled in said cooling chamber, said arbor defining a pressure chamber and discharge opening in the plane of said discharge duct for periodic registry therewith as said arbor is rotated; a sleeve slidable on said arbor and interposed cg between said discharge opening and fixed discharge duct, said sleeve having a plurality of metering ducts of graduated sizes, each adapted to be moved into registry with said discharge opening for periodic communication with said fixed 7c discharge duct; 9. fuel pump means incorporating said pressure chamber and having a. capacity in excess of the quantity admitted to said fixed discharge duct during registry of said discharge opening and metering ducts; means for discharg-= lit the excess fuel into said cooling chamber;

and means for bleeding excess fuel from said cooling chamber.

9. A liquid fuel injector as set forth in claim 6, wherein injection pump includes a piston extending from an end of said arbor and rotatable therewith; means urging said piston outwardly from said arbor; an extension on said casing enveloping the protruding end of said piston; and coacting cam means in said extension and on said piston to actuate said piston as said arbor 10 is rotated. 

